Fix a few error reports

[jonludlam]

And other miscellaneous fixes.

[Julow]

Needs formatting ! (dune build @fmt does format the dune files too)

[Julow]

This is whether the warning is not-affected by the "warn error" mode, it should stay false. The correct fix for the prefixes is #785

[jonludlam]

huh? so warn-error doesn't make all warnings errors? That doesn't make sense, does it?

[Julow]

Some warning are never turned into errors indeed.

[jonludlam]

Why?

[Julow]

"internal" warnings (most errors from linking) are never turned into fatal errors, as well as failures to lookup root modules.

[jonludlam]

Surely in that case it's an 'info' message rather than a warning, at the very least so people know the meaning of --warn-error

[Julow]

I think it's because these errors are caused by complicated things and the user can't really fix (bugs in odoc, things expected in the environment that Dune never give).
These things can be fixed but not for 2.0.1.

[jonludlam]

I've made #786 to sort this out, and added it to the 2.1 release project.

[Julow]

This diff is not necessary.
Reference errors are wrapped in "parent errors" because references are kind of an other language, errors don't mix.

Revert:

diff --git a/src/xref2/errors.ml b/src/xref2/errors.ml
index afba115b7..55469d03b 100644
--- a/src/xref2/errors.ml
+++ b/src/xref2/errors.ml
@@ -103,8 +103,7 @@ module Tools_error = struct
     | simple_module_type_expr_of_module_error
     | simple_module_lookup_error
     | signature_of_module_error
-    | parent_lookup_error
-    | reference_lookup_error ]
+    | parent_lookup_error ]
 
   let pp_reference_kind fmt k =
     let k =
@@ -166,7 +165,9 @@ module Tools_error = struct
     | `Parent_module e -> Format.fprintf fmt "Parent_module: %a" pp (e :> any)
     | `Fragment_root -> Format.fprintf fmt "Fragment root"
     | `Parent_type e -> Format.fprintf fmt "Parent_type: %a" pp (e :> any)
-    | `Reference e -> pp fmt (e :> any)
+    | `Reference e -> pp_reference_lookup_error fmt e
+
+  and pp_reference_lookup_error fmt = function
     | `Wrong_kind (expected, got) ->
         let pp_sep fmt () = Format.fprintf fmt " or " in
         Format.fprintf fmt "is of kind %a but expected %a" pp_reference_kind got
@@ -178,6 +179,7 @@ module Tools_error = struct
         | #reference_kind as kind ->
             Format.fprintf fmt "Couldn't find %a %S" pp_reference_kind kind name
         )
+    | `Parent e -> pp fmt (e :> any)
 end
 
 (* Ugh. we need to determine whether this was down to an unexpanded module type error. This is horrendous. *)
@@ -210,9 +212,6 @@ let is_unexpanded_module_type_of =
     | `OpaqueClass -> false
     | `Reference (`Parent p) -> inner (p :> any)
     | `Reference _ -> false
-    | `Wrong_kind _ -> false
-    | `Lookup_by_name _ -> false
-    | `Find_by_name _ -> false
   in
   inner
 
@@ -246,7 +245,6 @@ let rec kind_of_error : Tools_error.any -> kind option = function
   | `Parent (`Parent_expr e) -> kind_of_error (e :> Tools_error.any)
   | `Parent (`Parent_module e) -> kind_of_error (e :> Tools_error.any)
   | `Parent (`Parent _ as e) -> kind_of_error (e :> Tools_error.any)
-  | `Reference e -> kind_of_error (e :> Tools_error.any)
   | `OpaqueModule ->
       (* Don't turn OpaqueModule warnings into errors *)
       Some `OpaqueModule

[jonludlam]

Why on earth are reference errors 'parent' errors? That doesn't make sense either.

[Julow]

That's how the errors are constructed and destructed currently. I have a work-in-progress patch that entirely remove the "parent" thing but it's far from ready (https://github.com/Julow/odoc/tree/imp-tools-errors)

[jonludlam]

ugh. OK, let's leave it as-is for now and sort it out in 2.1

[Julow]

Looks good :)